Preparation of esters of alkanephosphonic acids



Patented Feb. 23, 1954 UNITED STATES TENT OFFWE PBEEAEAI QN. QF ERS. QF ALKANE- 33 53171 5 AQIDS Allen.- H'rLewis, Berkeley, and Richard- D. Stayner, Al ania, Qalif-i sisn t Ga ifcr a. li -search Corporation, San Francisco, Calif a corpora? i n. o De awar No Drawing. Original application February 4, 1948, Serial No. 6,345. Divided and this application. September 5, 1950, Serial No. 183,283

s r ss d he un on of. h dro i d b r philic radicals tr;v yield con'ipoimds having dc: s ab e. sur ace-a t e pro e ie It s g e l y known that long chain radicals of an aliphatic hydrocarbon structure exhibit hydrophobic properties, whereas, radicals derived from various.

oxygen acids such as those prepared from sulfur, phosphorus and the like have hydrophilic properties. The correct combination; of a hydrophobic radical and hydrophilic radical to yield a 001m pound of desired properties does not, however, follow any simple rule, such as, an'addition of therespective properties of the individual radicals in the compound,

It is the object of this invention to produce novel compounds.

It is also an object of this invention to produce novel esters of long chain alkanephosphonic acids.

A further object is to produce novel com-.

pounds with a combination of radical haying valuable. surface-active properties.

Qtherobjects are readily apparent in the desoription of this invention as hereinbefore DEBT. sented.

We have now'discovered that a novel class, of 5}."

compounds consisting oi oxyaikylene. esters of long-chain alkanephcsphonic acids in which an alky-l group containing 10-18. carbon atoms is attached to the phosphorus atoinhy a carbon to phosphorus bond and further characterized by the presence of an, ester grouping containingone ormore oxyalkylene divalent radicals, possesses valuable wetting, emulsifying and allied proper-. ties. These oxyalkylene esters of the long-chain alkanephosphonic acids may contain menus or polyoxyalkylene, divalent radicals to which are attached as terminal functional groups either an alkyl radical or a hydrogen atom and may be designated specifically as the alhyloxyalkylene, hydroxyalkyloxyalkylene and hydroxyalkyl esters. In general, the oxyalhylene, radical will contain at least 2 carbon atoms. These esters are. to be understood as inclusive oi theneutral; diesters, as ell s alt e te s... h ch the, res dual re n aceab e hydrceen 9 he. alkanepho nhon c. id,

mer ma n 1 0. re a e r me s ch, as an al a i m l.

elthc sh i ts m le t form these s ers. are shown to contain oxyalkylene radicals in a straight chain, it is tobe understood that substituted oxyalkylene radicals are also contemplated within the. scope of the invention. Those, oxyalkylene radicals which contain one or more hydrogen substituents in the form of an allgyl.

- group produce branched chain ester groupings.

which; are to be. understood as included in the, scope or the esters of the invention.

Our novel ester compounds of long chain allzanephosphonie acids containing at least one oxyalkylene radical may, for example, be de-v rived from mono-alkyl ethers of ethylene glycol, mcno-alkyl ethers of diethylene. glycol, and also from mono-alkyl ethers of triethylene glycol, as well as from themono-alkyl ethers of other polyethylene glycols in general. Compounds of this. invention with oxyallcylene. ester radicals of molecular weights upto about 600 possess valuable.

properties. The number of oxyalhylene groups in the ester radical accordingly is not a limiting factor. Also, we may use the monosalkyl ethers of propylene glycol or the dior tri-propylene glycols andofother polypropyleneglycols. When we use the hereinaboye presented. mono-.alkyl ethers of the, said glycols, we obtain ester compounds having an alkyloxyalkylene radical. By n. lkv q a ky en ra i a We m n a ical. characterized by the presence of a terminal alkyl roup linked to the ox-yallrylene radical through the, oxygen atom. By the term of oxyalkylene, we. mean the. divalent radical characterized by -..(R )r.Q. wherein n is a wholenumber of, 2 toabput 5, audit isselected from the group consisting of hydrogen and alkyl groups. Compounds such as butylene glycol, trimeth-ylene glys col, tetramethylene glycol and alkyl substituents thereof yield esters within the scope of our invention.

Furthermore, in lieu of the mono-alkylv ethers of the ethylene and polyethylene glycols, and the propylene and polypropylene glycols, we may use the polyalkylene. glycols per se, thereby obtaining the corresponding ester of alkanephosphonic acid having a bydroxyallcyloxyallzylene radical in the ester grouping. By the term hyroxyalkyloxyalkylene radical we mean a radical characterized by a hydroxy group attached to the, terminal allryl group of the hereinaboye e ned a ky sral y en a c l,-

I th cas s re 1. st r Qumrands, co tainbut individual oxyalkylene divalent radicals,

as distinguished from the polyoxyalkylene divalent radicals, we obtain the corresponding esters having hydroxyalkyl groups. These hydroxyalkyl esters, as well as hydroxyalkyloxyalkylene esters, we have discovered, are easily prepared by reacting long chain alkanephosphonic acids with an olefin oxide under suitable reaction conditions.

Our novel esters of the long-chain alkanephosphonic acids having more than one consecutive oxyalkylene radical therein may, for example, be prepared by reacting the corresponding long chain alkanephosphonyl dichloride with a compound having polyoxyallrylene radical containing a terminal hydroxyl group, via, a hydroxypolyoxyalkylene compound. In this reaction hydrogen chloride is formed, as well as the desired corresponding ester, thereby necessitating means for removal of said hydrogen chloride.

In this connection, it is to be noted that the preparation of compounds having a long-chain alkyl group of about carbon atoms or more attached to a phosphorus atom has been dificult of accomplishment until quite recently. However, a method of preparing such compounds easily has recently been discovered. In this novel method phosphorus trichloride is reacted with long-chain aliphatic compounds in the presence of oxygen to yield a long-chain alkanephosphonyl dichloride having the long-chain allryl group attached to the phosphorus atom by a primary, or preferentially by a secondary or tertiary carbon atom.

The method of carrying out this reaction is quite simple and comprises mixing the longchain hydrocarbon with phosphorus trichloride and thereafter bubbling oxygen through the mixture, the temperature being maintained at about 20 C. to about 60 C., until the reaction is complete. The reaction mixture is then subjected to reduced pressure distillation to remove unreacted long-chain hydrocarbon and any phos phorus oxychloride which may have been prepared and, lastly, the desired long-chain alkanephosphonyl dichloride is distilled over, also under reduced pressure.

In preparing our long-chain alkanephosphonyl dichlorides, we may use normal straight chain or branched chain aliphatic hydrocarbon compounds. While we may use substantially pure species of hydrocarbon compounds to form our long chain alkanephosphonyl dichlorides, we may nevertheless advantageously use mixed aliphatic hydrocarbons. Thus, petroleum fractions such as the kerosene, gas oil and similar fractions, hydrogenated olefin polymers and hydrogenated Fischer-Tropsch olefins react with phosphorus trichloride in the presence of oxygen to yield the desired aliphatic long chain alkanephosphonyl dichlorides.

In the preparation of our novel ester compounds by a preferred procedure, one mole of long-chain alkanephosphonyl dichloride is added to a mixture comprising at least 2 moles of oxyalkylene compound admixed with a substance capable of neutralizing the hydrochloric acid formed in the reaction, such as amines, pyridine, or the nitrogen bases in general, or other alkaline substances. Another method of preparing our novel esters consists in mixing long-chain alkanephosphonyl dichloride and the oxyalkylene compound at low temperatures with constant removal of the hydrogen chloride formed either by means of vacuum, or alternately by a gas stream of air, nitrogen or other inert gas. This,

method is fully described in our application Serial No. 6,345, filed in the U. S. Patent Office on February 4, 1948, now Patent No. 2,587,340, of which this application isa division.

In another method of preparing our novel hydroxyalkyl and hydroxyalkyloxyalkylene esters claimed in the present application, we may, for example, react long-chain alkanephosphonic acids with an olefin oxide, for example, ethylene oxide, propylene oxide or butylene oxide, to yield esters having oxyalkylene radicals in the molecule with a hydrogen atom attached to the terminal oxygen atom. For purposes of illustration, some of these ester compounds may, for example, be

shown by the following equation:

R3 R3 R2 R3 )2+ l I R'POz GH-CE orionopn 0 o wherein n is an integer of 1 to 10, R is a long chain alkyl of preferably 10 to 18 carbon atoms, and R 'and R represent hydrogen and short chain alkyl groups.

The reaction of alkylene oxides with alkane phosphonic acids may be carried out at atmospheric pressures, and the reaction temperature may be varied between the limits of 20-200 C. In the preparation of polyglycol esters, a surface catalyst may be used advantageously to increase the reaction rate, or other catalysts such as sulfuric acid, phosphoric acid, nickel sulfate, boron trifluoride, alkyl sulfates, sodium tertiary amines, etc., may be employed.

It has been discovered that the long-chain alkanephosphonic acids used for reacting with olefin oxides may be readily prepared from the corresponding dichlorides by reaction with a carboxylic acid according to the equation:

wherein R. is an alkyl group of 10 to 18 carbon atoms and R is an alkyl group such that the resulting acid chloride (B 0001) boils at a temperature below that of the long-chain alkanephosphonyl dichloride. Preferably the carboxylic acid is a low molecular weight acid such as acetic, propionic and the like.

' This latter process yields substantially quantitative amounts of the desired long-chain alkanephosphonic acid and, furthermore, yields a valuable acid-chloride by-product in contrast to the prior art by-product of dilute hydrochloric acid which results from hydrolysis of alkanephosphonyl dichloride with water. In carrying out this process, it is preferred to mix the ingredients and then heat the mixture for a few minutes at boiling temperatures, preferably under reflux. In compounding the reactant mixtures at least two moles of the carboxylic acid are used for each mole of long-chain alkanephosphonyl dichloride. After the heating period mentioned above, the acid-chloride is distilled off, followed by any excess carboxylic acid that may be present, preferably using reduced pressure. It has been discovered that the above procedure yields substantially quantitative amounts of the desired longchain alkanephosphonic acid in a highly purified condition.

By way of illustrating this process for producing long-chain alkanephosphonic acid from longchain alkanephosphonyl dichloride using carboxylic acid, the following example is presented: A mixture of 74.2 parts by weight of octadecanephosphonyl dichloride and 60 parts of glacial acetic acid was prepared and subsequently heated warmed on a steam bath for ac minutes.

to the boiling point. The acetyl chloride formed in the reaction was then distilled oil from the reaction mass. Next, the residue was subjected to reduced. pressure distillation to remove excess glacial acetic acid. The final product consisted of 67 parts by weight and was identified as octadecanephosphonic acid (CiaHaoPOs) by the following analysis:

Percent Phosphorus found 9.1 Phosphorus calculated 9.3 Chlorine found Trace The presence of but a trace of chlorine indicated that the final product was substantially pure, long-chain alkanephosphonic acid.

As previously stated, the half-esters of our novel compounds are also within the scope of our invention. These half-esters may, for example, be prepared by reacting molar amounts of hydroxy compounds, having an oxyalkylene radical and hydrogen or alkyl groups attached to the terminal oxygen atom, with long-chain alkanephosphonyl dichloride, dissolved in a solvent such as acetone or the like, to yield the corresponding ester monochloride which latter, on hydrolysis, yields the corresponding acid ester. The acid esters, on neutralization by ordinary procedures, yield the corresponding salts of the half-esters.

We have also discovered that the novel esters of our invention are effective wetting and/or emulsifying and/or penetrating and/or dispersing and/or detergency agents. Also, we have discovered that these novel compounds may be used efficiently as oil additives, textile treating agents, plasticizers and the like. By way of illustration of the esters of our invention, we submit the following examples:

Example 1.Monomethyl ether of ethylene glycol ester of octadecanephosphonic acid 37.1 parts of octadecanephosphonyl dichloride were added gradually to a mixture of 17 parts monoethyl ether of ethylene glycol and 30 parts of pyridine. After the addition the mixture was allowed to stand for minutes and then was The reaction mixture was then. cooled, diluted with .10 parts of water and acidified with I-lCl. The upper oily layer was extracted with parts of ether and washed with 50 parts of a half-saturated solution of sodium sulfate. The ethereal extract was dried and the solvent was evaporated to give a light-colored oil which was very slightly soluble in water. The material possessed the formula:

CmHs1{(OCH2CHzOCH3)2 Analysis of the ester:

Calculated phosphorus content 6.90 Found phosphorus content 7.36

This compound may be distilled with slight decomposition under reduced pressure at 220-225" C. at'3 min.

Example 2.Monobutyl ether of diethylene glycol ester of tetradecanephcsphonie acid 33 parts of tetradecanephcsphonyl dichloride were added gradually to a mixture of 36 parts of monobutyl ether of diethylene glycol and parts of pyridine. After reaction the ester prodact was obtained in thexsame manner as that outlined in Example 1." This product was a viscous,.'light-co1ored liquid which was slightly soluble in water and possessed the following formula:

Analysis of the ester:

Calculated phosphorus content 5.48 Found phosphorus content 5.22

This compound may be distilled with slight decomposition under reduced pressure at 230-234 C. at 3 mm.

Example 3.--Triethylene glycol ester of octadecanephosphonic acid 37.1 parts of octadecanephosphonyl chloride were added gradually to a mixture of 37.5 parts of triethylene glycol and 30 parts of pyridine. After reaction the ester product was obtained in the same manner as that outlined in Example 1. The product was a thick syrupy liquid which had the following formula:

The product on analysis gave:

Phosphorus found 5.6 Phosphorus calculated 5.2

Example 4.-Ethylene glycol ester of n-hemadecanephosphonic acid parts of n-hexadecanephosphonic acid were treated portionwise with 30 parts of ethylene oxide. The reaction mixture was allowed to warm to 35 C. at which temperature it was maintained for 30 minutes. The excess ethylene oxide was removed by warming the reaction mixture under reduced pressure to C. The product had the formula:

C1uHaaP(0CH2CHzOH)a Analysis:

Calculated phosphorus percent 7.9 Found do 7.7 Calculated hydroxyl number 284 Found hydroxyl number 280 Example 5.Pentaethylene glycol ester of n-o-ctadecanephosphom'c acid following formula:

CisHa1 l l[(0CH2C 2)s0E]:

Analysis:

Per cent Calculated phosphorus 3.9 Found phosphorus 4.0

The following Table I tabulates the wetting activity of some of our compounds. The tests for wetting activity were performed by noting the time in seconds required for a l-square-inch sample of standard #6 canvas to sink to the bottom when placed on the surface of 200 ml. of'solutio'n in a 259 ml. beaker.

TABLE I.-EVALUATION OF IVETTING ACTIVITY OF VARIOUS ESTERS OF VARIOUS ALKANEPHOSPHONIC ACIDS [Wetting times in seconds of 0.5% aqueous solutions of various esters of various alkanephosphonic Long Chain Alkyl=R The following Table II tabulates the emulsifying activity of some of our compounds. In these emulsification tests the prepared samples were shaken vigorously by hand, set aside and observed at regular time intervals.

ane phosphonyl dichloride weighed 197 parts and the boiling point was 200-215 C. at 5 mm. pressure.

In an analogous manner the normal dodecanephosphonyl dichloride, the normal tetradecane- TABLE II.EVALUATION OF THE EIVIULSIFYING ACTIVITY OF VARIOUS ESTERS OF VARIOUS ALKANEPHOSPYIONIC ACIDS 1 Minimum concentration of emulsifying agent capable of stabilizing a mixture of xylene-water (50) by volume for 5 days.

The novel long-chain alkanephosphonic esters appearing in Tables I and II were prepared from novel long-chain alkanephosphonyl dichloride precursors as outlined previously herein and as more specifically compounds illustrated in Tables I and II were prepared from pure normal straight chain hydrocarbons.

Illustrative example of preparation of a pure normal long chain alkanephosphonyl dichloride (viz., n-hexadecanephosphonyl dichloride) A solution of 452 parts by weight of n-hexadecane and 1000 parts by weight of phosphorus trichloride were placed in a reaction vessel equipped with a gas addition tube, water-cooled reflux condenser and a thermometer which dipped into the reaction mixture. The vessel was placed in a cold-Water bath and oxygen was passed through the solution for six hours at such a rate that the temperature did not rise over 45 C. The reaction proceeds more rapidly if the oxygen is made to pass through a fritted-glass plate. The reaction temperature finally fell to that of the water bath thereby indicating completion of the chemical reaction. Any phosphoryl chloride formed in the reaction was evaporated under reduced pressure and the residue distilled for the desired product. The fraction boiling at 140-145 C. at 5 mm. pressure weighed 160 parts and was recovered excess n-hexadecane. The n-hexadecillustrated below. All ester phosphonyl dichloride and the normal octadecane phosphonyl dichloride were obtained. As previously outlined, these long-chain phosphonyl dichlorides are precursors in the preparation of the esters presented in Tables I and'II.

We claim: I

1. The method of preparing hydroxy esters of long-chain alkane phosphonic acids, which comprises heating to a temperature in the range from about 20 to about 200 C. one mol of a long-chain alkane phosphonic acid containing from 10 to 18 carbon atoms in the alkane portion thereof with an even number up to 20 mole of an olefin oxide containing from 2 to 4 carbon atoms.

2. The method of preparing hydroxy esters of long-chain alkane phosphonic acids, which cornprises heating to a temperature in the range from about 20 to about 200 C. one mol of a longchain alkane phosphonic acid containing from 10 to 18 carbon atoms in the alkane portion thereof with an even number from 2 to 20 mols of an olefin oxide containing from 2 to 4 carbon atoms.

3. The method of preparing hydroxy esters of long-chain alkane phosphonic acids, which comprises heating to a temperature in the range from about 20 to about 200 0. one mol of a long-chain alkane phosphonic acid containing from 10 to 18 carbon atoms in the alkane portion thereof with an even number from 2 to 10 mols of an olefin oxide containing from 2 to 4 carbon atoms.

4. The method of preparing hydroxy esters of long-chain alkane phosphonic acids, which comprises heating to a temperature in the range from about 20 to about 200 C. a long-chain a1- kane phosphonic acid containing from 10 to 18 carbon atoms in the alkane portion thereof with an olefin oxide containing from 2 to 4 carbon atoms.

5. The method of preparing hydroxy esters of long-chain alkane phosphonic acids, which comprises heating to a temperature in the range from about 35 to about 155 C. a long-chain a1- kane phosphonic acid containing from 10 to 18 carbon atoms in the alkane portion thereof with an olefin oxide containing from 2 to 4 carbon atoms.

6. The method of preparing hydroxy esters of long-chain alkane phosphonic acids, which comprises heating to a temperature in the range References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,157,164 Daly et a1 May 9, 1939 2,872,244 Adams Mar. 27, 1945 2,382,309 Hamilton Aug. 4, 1945 

1. THE METHOD OF PREPARING HYDROXY ESTERS OF LONG-CHAIN ALKANE PHOSPHONIC ACIDS, WHICH COMPRISES HEATING TO A TEMPERATURE IN THE RANGE FROM ABOUT 20 TO ABOUT 200* C. ONE MOL OF A LONG-CHAIN ALKANE PHOSPHONIC ACID CONTAINING FROM 10 TO 18 CARBON ATOMS IN THE ALKANE PORTION THEREOF WITH AN EVEN NUMBER UP TO 20 MOLS OF AN OLEFIN OXIDE CONTAINING FROM 2 TO 4 CARBON ATOMS. 